Telescoping guard for hazelton propellers

ABSTRACT

A GUARD TO PROTECT DIVERS FROM THE BLADES OF A HAZELTON PROPELLER WHEREIN THE GUARD IS A TELESCOPING RING MOUNTED ON THE STABILITY SHROUD OF AN UNDERWATER VEHICLE. THE RING TELESCOPES FORWARD TO SURROUND THE PROPELLER.

Feb. 20, 1973 J. 'BERNAERTS 3,717,114

TELESCOPING GUARD FOR HAZELTON PROPELLERS Filed Feb. 23 1971 INVENTOR- HENRY BERN/15R rs 841% ATTORNEYS United States Patent US. Cl. 114-16 R 2 Claims ABSTRACT OF THE DISCLOSURE A guard to protect divers from the blades of a Hazelton propeller wherein the guard is a telescoping ring mounted on the stability shroud of an underwater vehicle. The ring telescopes forward to surround the propeller.

The invention described herein may be manufactured and used by or for the Government of the United States of America for government purposes with the payment of royalties thereon or therefor.

BACKGROUND OF THE INVENTION Field of the invention With the advent of the Hazelton propulsion system for use on underwater vehicles, great maneuverability as well as the ability to hover have resulted. These capabilities, along with deep submergence, have opened up or facilitated the use of underwater vehicles for many new missions. Notably, Hazelton propelled vehicles lend themselves to use in conjunction with divers for research and reconnaissance. However, the extra-vehicular activity of the divers poses problems of safety in that their proximity to the propellers could cause injury if they venture too close to them. This becomes a problem since it is often desirable to maintain headway during launching or retrieval of thedivers, and the Hazelton system employs tandem propellers, one at the bow and one at the stern of the vehicle.

It is, therefore, desirable to have a protection device for the divers while not inhibiting the performance or maneuverability of the vehicle used as a base of operations.

Description of the prior art The development of the Hazelton propeller is relatively recent and is continuing. However, there are no known protective devices for these propellers. Their design prevents adaptation of protection devices of conventional screw-type propellers. The Hazelton propeller has an annular hub which is of the same diameter and contour of the vehicle hull on which it is mounted. Therefore, when the blades are mounted on the hub they protrude into the stream well beyond the diameter of the hub. If any of the well known struts, skegs or cages were mounted to protect a Hazelton propeller, the extreme size of the resultant device would cause enormous drag and cause acoustic noise as well as stability problems.

The absence of protective structures for Hazelton propellers, and the unacceptability of adapting devices intended for use with conventional screw-type propellers, dictates a need which is fulfilled by the instant invention.

SUMMARY OF THE INVENTION Submersibles propelled by a Hazelton propulsion system have a stability shroud mounted aft of the rear propeller. The instant invention utilizes a ring that conforms to the circumference of the stability shroud and is telescopingly mounted on the leading edge thereof so that it can be extended forward to surround the propeller.

Thus, a minimum of extra structure is utilized to give divers full protection from the rotating blades.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of a submersible equipped with a Hazelton propeller with the subject invention installed thereon.

FIG. 2 is an end view looking forward from the rear of the submersible of FIG. 1.

DESCRIPTION OF THE INVENTION Referring now to the drawing, the aft end of a submersible 10, is shown with a Hazelton propeller assembly 12, installed thereon. To provide stability above a critical speed, a stability shroud 14, is mounted on the submersible 10, by a number of radial spokes or struts 16, connected to a shaft 18. The shaft 18, is in turn received in a hydraulic ram assembly 20, which positions the shroud 14, relative to the submersible 10, depending on stability requirements dictated by the speed of the submersible. The above structure and detail does not form a part of the instant invention but is set forth herein to show the environment in which the invention is to be used.

A protective ring assembly 22, is mounted on the forward or leading edge of the shroud 14. The ring assembly 22, has a circular ring or bar 24, that conforms to the circumference of the shroud 14, so as not to cause undue drag or turbulence. The ring 24, is mounted on the shroud 14, by a plurality of rods or struts 26. A minimum of three such struts 26, is dictated in order to insure the ring 24 is stable and able to withstand the load imposed by passage through the water and occasional impact with a diver.

The free ends of the struts 26, are received in cylindrical openings 28, in the shroud 14. The openings 28, are of a diameter approximately that of the struts 26, so as to frictionally engage the free ends thereof. In this way, the ring 24, can be manually positioned in an extended position, as shown in solid lines in FIG. 1, or any position therebetween and the frictional contact between the struts 26 and openings 28, will maintain the relative position of the ring, or other locking devices.

The manual positioning of the ring 24, is a simple and rugged installation with no intricate mechanism to fail. The use of such an installation is feasible since it is known before a mission whether a submersible will be used in conjunction with divers on extra-vehicular excursions. The ring 24, can then be positioned before a mission if it is needed, and left in its retracted or stored position, as shown in dotted lines in FIG. 1, during all other use. However, the ring 24, as can be seen in FIG. 1, is also an elfective guard against debris being fouled in the propeller and could be utilized as such when water borne debris or obstructions are likely to be encountered.

While the invention has been disclosed as a manually extendable ring 24, on a shroud 14, it is understood, and an obvious modification to use the cylindrical openings 28, as a cylinder to receive the struts 26, as pistons therein. In this way, the openings 28, and struts 26 could function as a hydraulic ram to extend and retract the ring 24. The use of hydraulic pressure in the ram assembly 20, would provide a ready source for the hydraulic fluid pressure.

As can be seen a simple but unique guard for a Hazelton propeller has been provided, which in operation does not hinder the performance of the vehicle but rather utilizes existing structure as a guide. The ring 24, when not in use, as shown in dotted line in FIG. 1, is retracted against and conforms in circumference to the stability shroud 14, normally associated with Hazleton propulsion systems. When it is desired to utilize the ring 24, as a protective device, it is extended, for example, as shown in solid lines in FIG. 1, to a' position where it encircles the propeller 12. It can also be extended forward of the plane of the rotating propeller 12, to prevent debris being drawn into the propeller. The simplicity of the design lends itself to modification, but any adaptation of the basic design to a particular installation would appear to be well within the scope of the invention.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A protective device for a propeller on a submersible comprising:

a stability shroud mounted with the leading edge thereof adjacent the aft end of the submersible;

a ring member having a fixed circumference corresponding to the circumference of the shroud and substantially greater than the circumference of the propeller; and

a plurality of struts telescopingly mounted in the leading edge of the shroud for movably mounting the ring on the shroud.

References Cited UNITED STATES PATENTS 3,066,893 12/1962 Mercier 42 X 3,532,129 10/1970 Ward et al. 13715.1 X

FOREIGN PATENTS 722,842 7/ 1942 Germany 115-42 MILTON BUCHLER, Primary Examiner S. M. GOLDSTEIN, Assistant Examiner 

